Hollow-core photonic bandgap fibers are a type of optical fibers used to guide light. Hollow-core fibers may offer advantages over conventional optical fibers such as lower Rayleigh scattering, reduced non-linearity, improved dispersion characteristics, lower phase sensitivity to ambient temperature, and lower transmission loss.
A polarizer is a device that may significantly attenuate one direction of polarization of electromagnetic radiation, while allowing the orthogonal direction of polarization to pass through with relatively low loss. Polarizers may be combined with optical fibers to modify the radiation passing through the fibers. In-fiber polarizers may have advantages over combined fibers and polarizers, such as easier alignment, smaller insertion loss, and better compatibility with optical fiber systems. Conventional in-fiber polarizers typically are based on side-polished fibers, D-shaped fibers coated with an extra layer of material on the flat side, or 45-degree tilted fiber Bragg gratings. However, existing in-fiber polarizers are based on solid-core fibers. These polarizers may not be fully compatible with hollow-core fibers, because of the difficulties associated with the connection between solid core fibers and hollow-core fibers.
It is therefore desirable to develop an improved in-fiber polarizer fabricated on a hollow-core photonic bandgap fiber. It is also desirable to develop an improved method of making an in-fiber polarizer.